Pipettes

ABSTRACT

The present invention provides a pipette having a body ( 2 ), a casing ( 4 ), sheathing the body ( 2 ), and a graduation means ( 6 ) located between the body ( 2 ) and the casing ( 4 ).

[0001] The present invention relates to pipettes, preferably, but notexclusively to graduated pipettes.

[0002] Graduated pipettes are commonly used in laboratories. Thegraduations are generally represented as a scale extending along thelength of the pipette.

[0003] Pipettes, especially those used in laboratories, are manufacturedas both disposable and non-disposable products. The method ofmanufacture of a pipette is generally determined by the expected use andservice life of the pipette. Disposable pipettes, both glass andplastic, are required to be more cheaply manufactured thannon-disposable pipettes, because they are often used only once beforedisposal. Therefore, disposable glass pipettes are usually made fromlight gauge glass and the graduation markings are applied with surfacebound inks that are less robust than those used in making non-disposablepipettes. Non-disposable pipettes are generally manufactured fromheavier gauge glass and the graduation marks are applied in such a wayas to be substantially permanent. In the case of non-disposablepipettes, enamel heat cured inks are sometimes used, but in other casesthe graduation marks are sintered into the glass using, for example,silver nitrate.

[0004] In both disposable and non-disposable pipettes, the markings areapplied to the exterior surface of the pipette.

[0005] There are several disadvantages to using this method ofconstruction to manufacture a non-disposable pipette. In the case ofenamel inks, the positioning of the graduation graphics on the surfaceleads to the marks being susceptible to contact with and environmentand/or chemicals with which the pipette may be used. Exposure toaggressive chemicals can lead to deterioration of the markings.Furthermore, enamel inks may contain heavy metals and other elementsthat may contaminate a chemical with which the pipette is used. Adisadvantage of using silver nitrate to create graduation markings isthat they can be produced in dark shades only. Dark markings can bedifficult to see when the pipette is used with dark liquids. Anotherdisadvantage of using silver nitrate results from the stringentenvironmental controls over its use, which are required in order to meetthe requirements of environmental agencies. Moreover, in providing anon-disposable pipette using known construction methods, if a singlestructural element is used, a better quality or more robust gauge ofglass must be used in order to reduce the likelihood of breakage.

[0006] It is an object of preferred embodiments to provide an improvedpipette.

[0007] The present invention provides a pipette comprising a body, acasing and a graduation means, wherein the body comprises an elongatetubular member, which body is sheathed along part, at least, of thelength thereof by the casing and the graduation means is located betweenthe body and the casing.

[0008] The present invention may comprise a disposable pipette, butpreferably provides a non-disposable pipette.

[0009] Suitably, the body has a tapered section at one end thereof. Thebody may comprise a tubular member of any suitable cross-sectionalshape. Preferably, the body comprises a tubular member of substantiallycircular cross-sectional shape.

[0010] The body may comprise any suitable material, for example,plastics material or glass.

[0011] The casing suitably has a similar conformation to the body.Suitably, the casing extends along sufficient length of the body tocover the whole of the graduation means. The casing may extend alongsubstantially the whole length of the body. If the body comprises atapered section, the casing may extend over the tapered section, butpreferably stops short of the tapered section.

[0012] The casing may comprise any suitable material. Preferably, thecasing comprises a plastics material. The casing advantageously providesa barrier between the graduation means and the external environment.

[0013] Suitably the casing is sealed at one, and preferably at both,ends thereof. The casing is suitably sealed in such a manner as torestrict, and preferably prevent, fluid entering between the body andthe casing.

[0014] The casing is suitably translucent and is preferablysubstantially transparent.

[0015] The graduation means may comprise graduation markings applieddirectly to the body, preferably to the exterior surface thereof, by anysuitable means. The graduation means may comprise graduation markingsapplied directly to the casing, preferably to the interior surfacethereof, by any suitable means.

[0016] Suitably, the graduation means comprises a substrate to whichgraduation markings have been applied. Suitably, the substrate is afilm. The film is suitably translucent and is preferably substantiallytransparent. Suitably, the substantially the whole, and preferably thewhole, of the substrate is sandwiched between the body and the casing.

[0017] Suitably, the material used to provide the graduation markingsprovides graduation markings that are coloured. Suitably, the graduationmarkings are coloured such that they are clearly visible when thepipette contains both a dark coloured liquid and a light colouredliquid. In this case, a pipette according to the present inventionadvantageously comprises graphics that are clearly visible whenpipetting liquid of any colour.

[0018] A pipette according to the present invention may further comprisea substance applied between the body and the casing to increase thetransparency of the pipette.

[0019] The present invention further provides a method of manufacturinga pipette, comprising the steps of, positioning a graduation meansbetween a body and a casing and sheathing part, at least, of the bodywith the casing such that the graduation means is located between thebody and the casing.

[0020] The method may comprise a method of manufacturing a disposablepipette, but suitably comprises a method of manufacturing anon-disposable pipette.

[0021] The method according to the present invention suitably comprisesa method of manufacturing a pipette according to the present invention.The method according to the present invention suitably comprises amethod of manufacturing a pipette having any of the features of thepipette according to the present invention.

[0022] Suitably, the exterior surface of the body is sheathed by thecasing.

[0023] The step of positioning the graduation means between the body andthe casing may comprise applying the graduation means to the body. Thegraduation means is preferably applied to the exterior surface of thebody.

[0024] Alternatively or. in addition, the step of positioning thegraduation means between the body and the casing may comprise applyingthe graduation means to the casing. The graduation means is preferablyapplied to the interior surface of the casing.

[0025] If the graduation means is applied to either the casing or thebody, any suitable method of application may be used. For example, ifthe graduation means comprises graduation markings, they may be printedor etched onto the surface of the body or the casing. By way of furtherexample, the graduation marking may be an integral part of either thebody or the casing. If the graduation means comprises a substrate towhich graduation markings have been applied, the substrate may beapplied to the body of the casing by adhesive or such like.

[0026] The graduation means need not be applied to either the casing orthe body, but may instead simply be located therebetween. In this case,the step of sheathing the body with the casing suitably fixes thegraduation means in the appropriate location.

[0027] A method according to the present invention may further includethe step of sealing the interface between the body and the casing.

[0028] Suitably, the step of sealing the interface between the body andthe casing involves providing a seal between part at least of theinterface between the casing and the body such that substantially noliquid can pass between the casing and the body.

[0029] Sealing the interface between the casing and the body may involveattaching part at least of the casing to the body. Suitably, one or bothends of the casing are attached to the body. Part, substantially thewhole or the whole of the casing may be attached to the body.

[0030] Alternatively, or in addition, a sealing means may be locatedbetween the casing and the body.

[0031] Embodiments of the present invention advantageously provide apipette equipped with graphics that are protected from contact with theenvironment and/or substances with which the pipette is to be used.Since the graphics of the graduation means are situated within thestructure of the pipette, the graphics may be provided by simple inks,rather than more expensive inks designed to with stand attack incorrosive environments.

[0032] Other advantages of the present invention resides in the use of abody and casing, which allows materials of inferior quality to be usedto make a more robust pipette. For example, materials that wouldpreviously only have been used to manufacture disposable pipettes, maybe used to provide a non-disposable pipette according to the presentinvention. Materials of inferior quality, formerly suitable to makepipettes of disposable quality only, may be imbued with superiorproperties that enable such materials to be used to make anon-disposable pipette of superior quality.

[0033] Location of the graduation means between the body and the casingin accordance with the present invention, advantageously provides apipette marked with graphics comprising inks that do not require hightemperature curing.

[0034] The casing of a pipette in accordance with the present invention,is also advantageous in providing structural reinforcement to thepipette.

[0035] Embodiments of the method of the present invention advantageouslyprovide a three element construction, used to simultaneously strengthenthe pipette and enable positioning of the graphics away from theexterior surface of the pipette to within the structure of the pipettewhere the graphics will not be attached by the environment about thepipette. Thus enabling manufacture of a pipette having indeliblegraphics provided by the graduation means, made by using simple printinginks capable of producing graphics in any colour.

[0036] A pipette according to embodiments of the present invention isadvantageously stronger than a conventional pipette made fromcorresponding materials. Embodiments of the present invention provide asubstantially unbreakable plastics non-disposable pipette withgraduation means that are substantially protected from environmentalattack and wear and tear. Such a pipette may comprise simple inks toprovide the graduation means such that graphics of any colour or shademay be provided and remain clearly visible when pipetting liquids of anycolour.

[0037] The present invention will now be described, by way of exampleonly, with reference to the following drawings, in which:

[0038]FIG. 1 is a perspective view of a pipette, and

[0039]FIG. 2 shows the pipette of FIG. 1 with a cut away section.

[0040]FIG. 1 shows a pipette comprising a body 2, providing an innerstructural element, a casing 4, providing an outer structural elementand a graduation means 6, providing graphics in the form of a graduationscale.

[0041] The body 2 comprises light gauge glass covered along part of itslength by the casing 4. The casing 4 comprises a plastics material.Preferably the plastics material is a chemically resistant plastic, suchas FEP. Such a casing provides a chemically resistant barrier to protectthe graduation means 6 from attack from the environment.

[0042] In order to prevent ingress of fluid between the body 2 and thecasing 4, the casing 4 is sealed against the body 2 at each end of thecasing 4.

[0043] The external surface of the body 2, is provided with a graduationmeans 6, in the form of a scale. The graduation means 6 comprises simpleprinting inks.

[0044] In an alternative embodiment, the body 2 comprises a chemicallyresistant plastics material, such as a fluoroplastic. In this case, asubstantially unbreakable non-disposable plastic pipette may beprovided.

[0045]FIG. 2 shows a pipette comprising a graduation means 6 comprisinga transparent material 8 upon which the graduation scale is printedusing suitable inks. The transparent film 8 is located between the body2 and the casing 4. The transparent material 8 is applied to the body 2by any suitable means, for example, the transparent material 8 may beself-adhesive and be applied in the form of a label.

[0046] The graphics of the graduation means 6 may comprise two-tonegraphics (not shown). In this case, the graphics will be more clearlyseen when pipetting fluids of any colour. For example, when pipettingdark liquids a dark scale would be almost invisible, but a lightershaded scale would be more clearly read.

1. A pipette comprising a body, a casing and a graduation means, whereinthe body comprises an elongate tubular member, which body is sheathedalong part, at least, of the length thereof by the casing and thegraduation means is located between the body and the casing.
 2. Apipette according to claim 1, wherein the pipette is a disposablepipette or a non-disposable pipette.
 3. A pipette according to claim 1,wherein the body comprises a tubular member of substantially circularcross-sectional shape.
 4. A pipette according to claim 1, wherein thebody comprises glass or plastics material.
 5. A pipette according toclaim 1, wherein the casing extends along sufficient length of the bodyto cover the whole of the graduation means.
 6. A pipette according toclaim 1, wherein the casing has a similar confirmation to the body.
 7. Apipette according to claim 1, wherein the casing is sealed in such amanner as to restrict fluid entering between the body and the casing. 8.A pipette according to claim 1, wherein the casing is transparent ortranslucent.
 9. A pipette according to claim 1, wherein the graduationmeans comprises graduation markings applied directly to the body and/orthe casing.
 10. A pipette according to claim 1, wherein the graduationmeans comprises a substrate to which graduation markings have beenapplied.
 11. A pipette according to claim 10, wherein the substratecomprises a film.
 12. A pipette according to claim 10, wherein thesubstrate is translucent or transparent.
 13. A pipette according toclaim 10, wherein the substrate is self adhesive
 14. A pipette accordingto claim 1, wherein the casing comprises a plastics material.
 15. Apipette according to claim 1, wherein the graduation means comprisesgraduation markings, and the graduation markings are coloured such thatthey are clearly visible when the pipette contains dark coloured liquidand when the pipette contains light coloured liquid.
 16. A pipetteaccording to claim 1, comprising a substrate between the body and thecasing to increase the transparency of the pipette.
 17. A method ofmanufacturing a pipette, comprising the steps of positioning agraduation means between a body and a casing, and sheathing part, atleast, of the body with the casing such that the graduation means islocated between the body and the casing.
 18. A method according to claim17, for manufacturing a pipette according to any one of claims 1-16. 19.A method according to claim 17, wherein the step of positioning thegraduation means between the body and the casing comprises applying thegraduation means to the body.
 20. A method according to claim 17,further comprising the step of sealing the interface between the bodyand the casing.